In that case you don't need to bias the coin, you can flat out learn to do a normal looking coin flip with catch and get a biased result.
Or decide whether or not to flip it by putting it on top of your other hand depending on how it landed when you caught it.
Put something on one side of the coin so you can feel what side is up and decide to flip it.
That's not biasing the coin itself though, it's rigging the whole flipping procedure.
If I toss a fair die and catch it in mid air with a robotic arm and high-speed camera so that I always catch it with the two face on top, it's still an unbiased die.
kevin_pet's coin would still be biased if it were caught. The article contends that you can bias the bouncing part of a coin flip, but not the falling part - GP proposes a coin with a biased falling motion.